Old English yrþling "plowman" (see earth (n.) + -ling); the sense of "inhabitant of the earth" is from 1590s and might be a re-formation, as the word seems to be missing in Middle English. Compare earthman. Earlier in this sense was earthite (1825).
Earth Day
earth-bound
earthen
earthenware
earthlight
earthling
earthly
earthman
earth-mother
earthquake
earthwork